The overall goal of this project is to extend our knowledge of the regulation of glucose production in humans and to improve our understanding of the role of glutamine in human substrate metabolism. The pI will test the hypothesis that the kidney is a gluconeogenesis organ in postaabsortive human by determing whoel body gltuamine gluconeogenesis and renal incroporation of glutamine into plasma glucose using infusions of U14 C glutamine and 6-H3 glucose in normal volunteers in conjunction with measurements of substrate balance across the kidney.